Walrus

The Walrus' Latin name, Odobenus rosmarus, means "tooth-walking sea cow." The walrus uses its prominent tusks to pull its bulk from the ocean onto pack ice. The process looks like the walrus is walking on its tusks, hence the name. The walrus is a single species but has two subspecies—the Pacific Walrus and the Atlantic Walrus. Both subspecies are similar in appearance, diet and behavior with the Pacific Walrus tending to be a little larger. Atlantic Walruses are found in the Eastern and High Arctic, including Baffin Bay and Lancaster Sound. The Pacific Walrus inhabits the Bering, Chukchi, and Laptev Seas.

The most recognizable characteristics of the walrus are its long tusks and whiskery mouth. The tusks are modified upper canines. They are used to help the walrus "haul out" and open escape and breathing holes in ice floes. Both males and females grow tusks, but male tusks are generally longer. Tusks are not used when gathering food, but they do play an important role in mating and dominance displays among bulls (male walruses). The displaying of tusks, followed by their use as weapons, helps establish hierarchy within the herds and ownership of female harems. The skin on the back and neck of a walrus is particularly thick to protect them from "tusking," but injury frequently occurs, and occasionally, death.

The walrus' whiskers, or vibrissae, are not hairs, but extremely sensitive, tactile organs, much like a cat's whiskers. As the walrus roots about in the poor visibility of the ocean bottom, its vibrissae (which are attached to an extensive neural system) relay tactile information to the brain, helping it to find food. The walrus eats mollusks, snails, crabs and sea cucumbers. It may occasionally eat fish, octopus or even seal if other food sources are scarce.

Walrus are massive animals. They easily reach weights of 2,000 – 3,000 lbs and can grow to 12 feet in length. The only pinniped that can outgrow a walrus is the Elephant Seal. Walruses have a thick hide and a generous blubber layer that keeps them warm as they swim in the arctic waters and lay on the pack ice. The skin on the bottom of their flippers is thick and rough to provide protection and traction on the ice. The walrus's hind flippers can rotate under its pelvis, allowing it to walk on all fours. Walruses are generally a grayish-brown in color, but this can change do to a network of small blood vessels in their skin layer. In cold water, the blood vessels contract, preserving body heat and the walrus can appear almost white. Conversely, when the walrus is basking in the arctic sun, the blood vessels dilate to cool the body and give the walrus a red sun-burned look.

Walruses are extremely noisy and social, cramming onto beaches and ice floes by the thousands. Walruses segregate their herds - males, females and females with calves. Walrus mothers are very protective of their young and shelter them between their foreflippers. If danger approaches, the mother will grab her calf with her flippers and dive into open water. Calves will frequently ride on their mother's back while swimming and while on land. Elevating the calf from the tight packing of the herd keeps them from being accidentally crushed. Males who seek to mate swim in front of beached herds of receptive females, creating visual and vocal displays. Females who are interested leave the ice and mating takes place in the water. Due to delayed implantation of the embryo, gestation lasts 15 months. Walrus cows haul out to give birth to their one calf. The calf will stay with her and her herd, being nursed and protected for the next 2 years. At this time, the female will be ready to mate again. If the calf is male, he will leave his mother to join his own all-male herd. If the calf is female, she will usually stay with her mother's herd.

Fun Walrus Facts

- Walruses have been close to extinction on a couple of occasions due to overhunting. Walrus tusks, oil, skin and meat were highly valued in the 18th and 19th centuries. Only indigenous peoples of the arctic are currently allowed to hunt walrus and there is a limit on numbers that can be killed.

- Walruses make noise both above and below the water. They are the most garrulous of pinnipeds and snort, roar, whistle, grunt, bark, rasp and click. Below the water they will click, nock and tap as well as make bell-like sounds from air sacs in their pharynx.

- When startled, walruses stampede for open water, occasionally crushing calves in the process. This is probably why most females and calves form separate herds.

- Walruses don't have very good eyesight, but their hearing and sense of smell is excellent. Touch is also an important sense in walrus communities. Walruses seek physical contact with each other.

- Walruses squirt jets of water from their mouths to excavate shellfish, clams and other food.